1. Field of the Invention
The invention relates to a method for providing quality of service to a user of a Mobile Terminal (MT) in a packet data network.
2. Description of the Related Art
The prior art provides an end-to-end bearer resources management for a negotiated QoS within a packet data network. Third Generation Partnership Project 2 (3GPP2) specifications, as described in the All-IP Core Network Multimedia Domain (3GPP2 specifications), X.S0013-000-0 v1.0 published in December 2003 by 3GPP2, provide a segmented end-to-end model. This model exploits the information available from an application signaling protocols such as in Session Initiation Protocol (SIP) to request the bearer resources on both a “local” network such as a Packet Core Network (PCN) and a “remote” network such as an Internet Protocol (IP) Multimedia Subsystem (IMS) of an end-to-end bearer channel of a packet data network. Each end-to-end bearer channel is managed as three distinct segments: the access network for the originating side of the session such as the PCN (local segment), a backbone network, and the access network such as the IMS (remote segment) for the terminating side of the session. The segmented model allows for each segment where resources are allocated to either maintain per-flow reservations and carefully manage resource usage or employ other bearer resource management methods for Mobile Terminals (MTs).
3GPP2 addresses the authorization of bearer resource associated with the local segment and the remote segment, and assumes that in these segments that the resources are managed on a per flow basis.
In the segmented end-to-end model, bearer resources are reserved before a MT is notified that another MT is attempting to initiate a communication. After a first phase of the application signaling, both MTs have completed capability negotiations and know the bearer resource requirements for an end-to-end bearer channel. Subsequently, the MTs request the bearer resources on their respective segments (local or remote). The access network using a Packet Data Service Node grants bearer resources, forwards a bearer resource request to the backbone segment. If there are insufficient bearer resources available for a session, the session is terminated.
As regards to 3GPP2 specification, one solution may be to generate a token at a P-CSCF in the remote network (IMS network). The token consists of a Proxy Call Session Control Function (P-CSCF) IP address and a session identity, which will be sent to a Mobile Terminal (MT) from the P-CSCF. The P-CSCF is the initial interface (SIP Server) between the MT and the IMS. The MT would provide that information to the PDSN in the PCN, which subsequently provides it to a Packet Data Function (PDF) located between the local segment and the access segment. The PDF uses the token information to communicate with the P-CSCF to request the session information and correlates the information between the local network and the remote network. However, a problem is the impact on the IMS to generate the token. Although it seems reasonable to require a P-CSCF to generate a token, that may not be a reasonable requirement for non-SIP network entity such as an Real Time Streaming Protocol (RTSP) server. RTSP is defined in RFC 2326, published in April 1998 by the Engineering Task Force. The RTSP is a client-server multimedia presentation control protocol, designed to address the needs for efficient delivery of streamed multimedia over IP networks.
A solution could be to generate the token at the PDF, but that requires the P-CSCF to discover the PDF and this may cause a high consumption of resources in the remote network. For that reason, there is a need to save resources on the remote network while providing a level of services to MTs that use a local and a remote network for communicating with another MT or for receiving packet data services from the remote network. The invention provides a solution to this problem.